The brand-new ThinkPad X1 Nano only tips the scale at little more than 900 grams. But it is not only the lightest ThinkPad, it is also the first model to return to 16:10 panels. However, Lenovo had to make some compromises to realize such a compact device, which is apparent by the limited number of ports and the reduced key travel.
https://www.notebookcheck.net/Lenovo-s-ThinkPad-X1-Nano-ist-the-lightest-ThinkPad-you-can-buy.519341.0.html